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MANUFACTURING AND DESIGN OF INSULATION SYSTEM FOR AIR COOLED TURBO GENERATOR BY V.P.I PROCESS
Profile of B.H.E.L
Bharat Heavy Electrical Limited (BHEL) is today the largest engineering enterprise of India with an excellent track record of performance BHEL manufactures over 180 products and meets the needs of core-sectors like power, industry, transmission, transportation (including railways), defense, telecommunications, oil business, etc. Products of BHEL make have established an enviable reputation for high quality and reliability
Preface
Power is the basic necessity for economic development of a country. production of electrical energy its per capital consumption deemed as an index of standard of living. An AC generator works on the principle of ‘Electro Magnetic Induction’.
Turbo generators are machines which can generate high voltages and capable of delivering KA of currents The designer should be cautious in designing the winding insulation. Insulation design plays a major role on the life of the Turbo Generator
Introduction
First half we discuss about manufacture of a Generator. The latter half we explain the insulation design. We more over stress on stator manufacture and on VPI Process
Manufacture of Generator
Generator manufacturing can be broadly divided into three main parts: 1. Stator manufacture 2. Rotor manufacture 3. Exciter manufacture
fLowchart of various stages I a generator manufacture
STATOR MANUFACTURE PROCESS:
Stator core construction and Coil construction and their assembly.
Stator core construction PREPARATION OF STATOR LAMINATIONS RECEPTION OF SILICON STEEL ROLLS SHEARING
BLANKING AND NOTCHING
DEBURRING OPERATION: VARNISHING: sheets are dried at a temperature of around 260 – 350 oC 12-18microns Quality Check: xylol test Mandrel Hardness – 7H I.R – 20 laminatons 1m ohm
. STATOR CORE ASSEMBLY
A TRAIL PACKET ASSEMBLY B NORMAL CORE ASSEMBLY i) Stepped packed assembly ii) Normal packet assembly a) In process pressings 150 kg/cm2 b) Fitting of clamping bolts:
STATOR WINDING INSULATION SYSTEM FEATURES
Strand Insulation Turn Insulation Ground wall Insulation Slot discharges
Picture of above shit CLASSIFICATION OF INSULATING MATERIAL: According to materials According to temperature
Stator Winding
The most prime part of a winding is insulation
Resin Impregnation
Epoxy resins
MANUFACTURE OF STATOR COILS
A) For resin poor process
Reception of copper conductors Transposition Putty operation Stack consolidation Bending Final taping
B) FOR RESIN RICH PROCESS
Putty work Final taping Final baking
•
ADVANTAGES OF RESIN RICH SYSTEM OF INSULATION: Better quality and reliability is obtained In case of any fault (phase - ground/ phase – phase short) carrying the repair process is very easy. Addition of excess resin will be avoided because of using resin rich mica tape
•
DISADVANTAGES OF RESIN RICH SYSTEM OF INSULATION: It is a very long procedure Due to fully manual oriented process, the cost is more It is possible to process stator bars only. Even though the advantages and disadvantages of both the process are explained above, resin poor process is the best of all, as the resin content used is almost only 35% compared to resin poor process and also show good insulation properties justified in the later sections.
10.1 ADVANTAGES OF RESIN POOR SYSTEM OF INSULATION: It has better dielectric strength Heat transfer coefficient is much better It gives better capacitance resulting in less dielectric losses due to which the insulation life will be more The cost will be less and it is latest technology Reduction in time cycle and consumption for MW also less and it gives high quality
DISADVANTAGES OF RESIN POOR SYSTEM OF INSULATION: If any short circuit is noticed, the repairing process is difficult and need of excess resin from outside. Dependability for basic insulating material on foreign supply
THE VPI PROCESS
INTRODUCTION TO VACUUM PRESSURE IMPREGNATION SYSTEM Drawback of earlier VPI SYSTEM Failures were due to two types of problems: Tape separation Excessive relaxation of the main ground insulation
Vacuum Pressure Impregnation of resin poor insulated jobs
Preheating:the completed stator for period of 12 hrs at 60 deg ,temp>85deg Lifting and shifting Vacuum cycle: vacuum pressure of about 0.2 mb is maintained for about 17 HRS Vacuum drop test Heating the resin
Resin admission. Resin settling Pressure cycle: subject resin to pressure cycle of 4 kg/ cm2 of dry nitrogen, subj for 2 hrs. Aeration Post curing cycle Cleaning
FACILITIES AVAILABLE IN VPI PLANT IN BHEL
Steam furnace for preheating Size of chamber: 2 * 2 * 6.5 M Maximum temperature: 160°C Electrical power consumption: 75KW Work place: 1425 Work centre: 3215 Stream inlet: 200-250°C
Date and time
RTD-I(°C)
RTD-II(°C)
Furnace air temperature
Remarks Rotor temperatur e is reached to 60±3°C at 2:00hrs on 31.5.2007 and it is maintained for 4 hrs i.e., up to 6:00 on 31.5.2007
30.5.2007
19:00
32.0
30.0
45.6
30.5.2007
20:00
45.4
48.6
57.9
30.5.2007
21:00
49.9
50.9
63.4
30.5.2007
22:00
52.5
54.3
70.5
30.5.2007
23:00
53.3
55.1
73.4
30.5.2007
24:00
56.6
57.3
75.6
31.5.2007
1:00
59.9
60.2
75.1
31.5.2007
2:00
62.4
63.9
77.0
31.5.2007
3:00
62.3
64.7
77.0
Rotor is switched to vac 140 tank at 7:00 hrs on 31.5.2007
31.5.2007
4:00
63.3
64.1
75.0
31.5.2007
5:00
63.3
64.0
75.6
31.5.2007
6:00
63.1
63.7
75.6
Date and Time
Resin cycle
Vacuum in graph (mbar)
Vacuum in meter (mbar)
Job temperature (°C)
8.5.2007 22:00
--
--
54.37
Resin tanks 025,102 are heated for impregnation
8.5.2007 0:00
--
--
54.89
Viscosity of resin at 60°C is 33CP
9.5.2007 2:00
--
--
59.02
Viscosity after aging is 36.10CP
9.5.2007 3:30
0.65
0.65
61.6
9.5.2007 and 10.5.2007
9.5.2007 5:30
0.41
0.40
63.59
Resin admission started at 19:45hrs
9.5.2007 7:30
0.28
0.29
64.2
Resin admission completed at 19:55hrs
9.5.2007 9:30
0.22
0.22
63.2
Pressurisation started at 20:00hrs
9.5.2007 11:30
0.19
0.19
62.3
Pressurisation of 4kg/sq.cm reached at 21:20hrs
9.5.2007 13:30
0.18
0.18
62.1
Pressurisation hold up for 3hrs is at 0:20hrs
9.5.2007 15:30
0.17
0.17
62.0
Resin withdrawn to storage tanks is from 0:30hrs –1:00hrs
9.5.2007 17:30
0.14
0.14
61.8
Stator loaded in hot air furnace from 1:00hrs – 1:30hrs on 10.5.2007
Date and Time
ESOH 15T
TSOH 06B
ESW 02
TSW 13
Core
Room temperature
10.5.2007 1:30hrs
70.0
76.4
62.4
62.5
63.4
33.1
10.5.2007 4:30hrs
126.7
131.4
94.7
102.3
98.8
31.7
10.5.2007 7:30hrs
144.3
154.1
125.4
134.5
126.1
31.6
10.5.2007 10:30hrs
147.7
154.9
139.9
145.1
140.6
34.8
10.5.2007 13:30hrs
137.6
144.4
139.3
141.6
140.7
38.0
10.5.2007 16:30hrs
136.9
144.2
140.0
140.9
140.6
38.4
10.5.2007 19:30hrs
140.2
143.6
140.1
140.7
140.2
37.2
Remarks
10.5.2007 22:30hrs
144.4
151.3
143.7
145.1
144.1
35.9
11.5.2007 1:30hrs
143.1
146.7
145.2
145.1
145.2
33.8
11.5.2007 4:30hrs
144.3
151.0
143.6
144.0
144.7
31.1
11.5.2007 7:30hrs
135.7
142.1
144.3
145.1
145.0
31.3
11.5.2007 10:30hrs
135.0
135.7
135.1
135.0
135.8
34.8
11.5.2007 13:30hrs
135.6
141.4
135.4
135.6
135.9
38.3
11.5.2007 17:30hrs
148.0
149.2
142.8
142.2
142.1
39.8
Job temp. is reached to 140±5°C i.e., from 136.2°C to 145.6°C at 9:30hrs on 10.5.2007 and it is maintained for 32hrs i.e. up to 17:30hrs on 11.5.2007.
Furnace is switched off at 17:30hrs on 11.5.2007 and circulation fans kept running till the job temperature is reached from 70°C- 75°C
Impregnated tubs for keeping jobs For vertical impregnation: As per respective tech. Document. For horizontal impregnation: As per respective tech. Document
Specifications of plant: Impregnation medium Epoxy resin (class F solvent free) and hardener mix in 1:1 ratio as per TG34967 Epoxy resin (class F solvent free) and hardener mix in 1:1 ratio as per TG34931 Horizontal impregnation chamber Diameter: 4000mm Cylindrical length: 9000 mm Operating over pressure: 6 bar Operating vacuum: 0.15 mbar Operating temperature: 90°C Loading weight of impregnation object: maximum of 120 tonnes Maximum leakage rate: less than 1mbar/lit/sec. Moving load: 140 tonnes. Static load: 170 tonnes
Pressure medium for impregnation Pressure medium: dry nitrogen Operating pressure: 6 bar. Nitrogen storage capacity: 52cubic meter at 25 bar. Resin storage capacity Total storage: 5*9000L+1*3000L Operating parameters of each tank Operating vacuum: 0.5mbar Operating over pressure: 0.5bar Operating temperature: 80°C Resin filters(stainless steel washable) Filter fineness: 150microns Output (maximum): 1000lits/min
Vacuum system Root pumps: 2No.s, 5.5KW each Suction capacity: 2000cubic meter/hr Vacuum pumps(4No.s, 7.5KW each) Suction capacity: 250 cubic meter/hr This system is provided with separator filter with activated carbon filters, to protect the vacuum pumps from resin and hardener vapours. Refrigeration system The resin inside the tanks has to be stored at 10±2°C. this can be stored for indefinite period with a brine chilling/refrigeration system. The brine storage capacity: 1*25000L+1*26000L Composition of brine: 40%Mono Ethylene glycol and 60%water Heating and cooling system The heating of resin in the storage tanks and the impregnation chamber is by circulating the heated brine through the heat exchangers, to heat by saturated steam. The hot brine is cooled to about 40°C by circulating water through coolers and then the brine is chilled to -10°C and stored in the tanks. Post heating of job Explosion proof steam drier and electrical heating superposed. Size: 7*4.5*4.5M Maximum weight of job: 80 tonnes Maximum temperature: 150°C Indirectly heated hot air circulating oven (gas fired) Size: 9*4.5*4.5M Maximum weight of job: 170 T/120T with facility for rotation. Maximum temperature: 150°C
DATA COLLECTION OF SAMPLES
INDO-BHARAT-II ROTOR
RESIN POOR SYSTEM
• • • • • •
RESIN RICH SYSTEM
The insulation tape used in this system has 40% resin. This method follows thermosetting process. There is a need for addition of resin from outside. Reduction in time cycle for this process
•
No tests are carried out while at processing Processing of bars along with stator and with conductors and processing of exciter Coils along with exciter is possible.
•
•
The cost of repair is more
•
The overall cost is less compared to resin rich system.
• • •
• • •
The insulation tape used in this is 7% of 40% resin. Same as in resin poor. Further addition of resin is not required from outside. It is very long process and time consuming while at processing stage. Tests are being carried out Stage. Processing of stator bars is only possible in resin rich systems. Repairing work is easy. The total cost in this process is more.
JUSTIFICATION
Justification can be done by two tests HV and TAN δ tests
PRESENT INSULATION SYSTEMS IN THE WORLD
1. Vacuum pressure impregnation (VPI) of individual coils and bars 2. Global VPI of complete stators 3. Hydraulic molding of individual coils and bars using resin-rich tapes 4. Press curing of individual coils and bars, also using resin-rich tapes
Westinghouse Electric Co.: Thermalastic™ General Electric Co. :Micapals I anII™,EpoxyMicaMat™, Micapal HT™, and hydromat™ Alsthom, GEC Alsthom, Alstom Power: Isotenax™, Resitherm™,
Siemens AG, KWU: Micalastic™
ABB Industrie AG: Micadur™, Toshiba Corporation: Tosrich™ and Tostight- I™ Mitsubishi Electric Corporation Hitachi, Ltd.: Hi-Resin™, Hi-Mold™, and Super Hi-Resin™ Summary of Present-Day Insulation Systems
A NEW hype IN INSULATION SYSTEM
MICALASTIC The MICALASTIC Insulation in ITAIPU™ Manufacturing and Design Fitting of Roebel Bars into Slots: Thermal Stability
CONCLUSION:
Profile of B.H.E.L
Bharat Heavy Electrical Limited (BHEL) is today the largest engineering enterprise of India with an excellent track record of performance BHEL manufactures over 180 products and meets the needs of core-sectors like power, industry, transmission, transportation (including railways), defense, telecommunications, oil business, etc. Products of BHEL make have established an enviable reputation for high quality and reliability
Preface
Power is the basic necessity for economic development of a country. production of electrical energy its per capital consumption deemed as an index of standard of living. An AC generator works on the principle of ‘Electro Magnetic Induction’.
Turbo generators are machines which can generate high voltages and capable of delivering KA of currents The designer should be cautious in designing the winding insulation. Insulation design plays a major role on the life of the Turbo Generator
Introduction
First half we discuss about manufacture of a Generator. The latter half we explain the insulation design. We more over stress on stator manufacture and on VPI Process
Manufacture of Generator
Generator manufacturing can be broadly divided into three main parts: 1. Stator manufacture 2. Rotor manufacture 3. Exciter manufacture
fLowchart of various stages I a generator manufacture
STATOR MANUFACTURE PROCESS:
Stator core construction and Coil construction and their assembly.
Stator core construction PREPARATION OF STATOR LAMINATIONS RECEPTION OF SILICON STEEL ROLLS SHEARING
BLANKING AND NOTCHING
DEBURRING OPERATION: VARNISHING: sheets are dried at a temperature of around 260 – 350 oC 12-18microns Quality Check: xylol test Mandrel Hardness – 7H I.R – 20 laminatons 1m ohm
. STATOR CORE ASSEMBLY
A TRAIL PACKET ASSEMBLY B NORMAL CORE ASSEMBLY i) Stepped packed assembly ii) Normal packet assembly a) In process pressings 150 kg/cm2 b) Fitting of clamping bolts:
STATOR WINDING INSULATION SYSTEM FEATURES
Strand Insulation Turn Insulation Ground wall Insulation Slot discharges
Picture of above shit CLASSIFICATION OF INSULATING MATERIAL: According to materials According to temperature
Stator Winding
The most prime part of a winding is insulation
Resin Impregnation
Epoxy resins
MANUFACTURE OF STATOR COILS
A) For resin poor process
Reception of copper conductors Transposition Putty operation Stack consolidation Bending Final taping
B) FOR RESIN RICH PROCESS
Putty work Final taping Final baking
•
ADVANTAGES OF RESIN RICH SYSTEM OF INSULATION: Better quality and reliability is obtained In case of any fault (phase - ground/ phase – phase short) carrying the repair process is very easy. Addition of excess resin will be avoided because of using resin rich mica tape
•
DISADVANTAGES OF RESIN RICH SYSTEM OF INSULATION: It is a very long procedure Due to fully manual oriented process, the cost is more It is possible to process stator bars only. Even though the advantages and disadvantages of both the process are explained above, resin poor process is the best of all, as the resin content used is almost only 35% compared to resin poor process and also show good insulation properties justified in the later sections.
10.1 ADVANTAGES OF RESIN POOR SYSTEM OF INSULATION: It has better dielectric strength Heat transfer coefficient is much better It gives better capacitance resulting in less dielectric losses due to which the insulation life will be more The cost will be less and it is latest technology Reduction in time cycle and consumption for MW also less and it gives high quality
DISADVANTAGES OF RESIN POOR SYSTEM OF INSULATION: If any short circuit is noticed, the repairing process is difficult and need of excess resin from outside. Dependability for basic insulating material on foreign supply
THE VPI PROCESS
INTRODUCTION TO VACUUM PRESSURE IMPREGNATION SYSTEM Drawback of earlier VPI SYSTEM Failures were due to two types of problems: Tape separation Excessive relaxation of the main ground insulation
Vacuum Pressure Impregnation of resin poor insulated jobs
Preheating:the completed stator for period of 12 hrs at 60 deg ,temp>85deg Lifting and shifting Vacuum cycle: vacuum pressure of about 0.2 mb is maintained for about 17 HRS Vacuum drop test Heating the resin
Resin admission. Resin settling Pressure cycle: subject resin to pressure cycle of 4 kg/ cm2 of dry nitrogen, subj for 2 hrs. Aeration Post curing cycle Cleaning
FACILITIES AVAILABLE IN VPI PLANT IN BHEL
Steam furnace for preheating Size of chamber: 2 * 2 * 6.5 M Maximum temperature: 160°C Electrical power consumption: 75KW Work place: 1425 Work centre: 3215 Stream inlet: 200-250°C
Date and time
RTD-I(°C)
RTD-II(°C)
Furnace air temperature
Remarks Rotor temperatur e is reached to 60±3°C at 2:00hrs on 31.5.2007 and it is maintained for 4 hrs i.e., up to 6:00 on 31.5.2007
30.5.2007
19:00
32.0
30.0
45.6
30.5.2007
20:00
45.4
48.6
57.9
30.5.2007
21:00
49.9
50.9
63.4
30.5.2007
22:00
52.5
54.3
70.5
30.5.2007
23:00
53.3
55.1
73.4
30.5.2007
24:00
56.6
57.3
75.6
31.5.2007
1:00
59.9
60.2
75.1
31.5.2007
2:00
62.4
63.9
77.0
31.5.2007
3:00
62.3
64.7
77.0
Rotor is switched to vac 140 tank at 7:00 hrs on 31.5.2007
31.5.2007
4:00
63.3
64.1
75.0
31.5.2007
5:00
63.3
64.0
75.6
31.5.2007
6:00
63.1
63.7
75.6
Date and Time
Resin cycle
Vacuum in graph (mbar)
Vacuum in meter (mbar)
Job temperature (°C)
8.5.2007 22:00
--
--
54.37
Resin tanks 025,102 are heated for impregnation
8.5.2007 0:00
--
--
54.89
Viscosity of resin at 60°C is 33CP
9.5.2007 2:00
--
--
59.02
Viscosity after aging is 36.10CP
9.5.2007 3:30
0.65
0.65
61.6
9.5.2007 and 10.5.2007
9.5.2007 5:30
0.41
0.40
63.59
Resin admission started at 19:45hrs
9.5.2007 7:30
0.28
0.29
64.2
Resin admission completed at 19:55hrs
9.5.2007 9:30
0.22
0.22
63.2
Pressurisation started at 20:00hrs
9.5.2007 11:30
0.19
0.19
62.3
Pressurisation of 4kg/sq.cm reached at 21:20hrs
9.5.2007 13:30
0.18
0.18
62.1
Pressurisation hold up for 3hrs is at 0:20hrs
9.5.2007 15:30
0.17
0.17
62.0
Resin withdrawn to storage tanks is from 0:30hrs –1:00hrs
9.5.2007 17:30
0.14
0.14
61.8
Stator loaded in hot air furnace from 1:00hrs – 1:30hrs on 10.5.2007
Date and Time
ESOH 15T
TSOH 06B
ESW 02
TSW 13
Core
Room temperature
10.5.2007 1:30hrs
70.0
76.4
62.4
62.5
63.4
33.1
10.5.2007 4:30hrs
126.7
131.4
94.7
102.3
98.8
31.7
10.5.2007 7:30hrs
144.3
154.1
125.4
134.5
126.1
31.6
10.5.2007 10:30hrs
147.7
154.9
139.9
145.1
140.6
34.8
10.5.2007 13:30hrs
137.6
144.4
139.3
141.6
140.7
38.0
10.5.2007 16:30hrs
136.9
144.2
140.0
140.9
140.6
38.4
10.5.2007 19:30hrs
140.2
143.6
140.1
140.7
140.2
37.2
Remarks
10.5.2007 22:30hrs
144.4
151.3
143.7
145.1
144.1
35.9
11.5.2007 1:30hrs
143.1
146.7
145.2
145.1
145.2
33.8
11.5.2007 4:30hrs
144.3
151.0
143.6
144.0
144.7
31.1
11.5.2007 7:30hrs
135.7
142.1
144.3
145.1
145.0
31.3
11.5.2007 10:30hrs
135.0
135.7
135.1
135.0
135.8
34.8
11.5.2007 13:30hrs
135.6
141.4
135.4
135.6
135.9
38.3
11.5.2007 17:30hrs
148.0
149.2
142.8
142.2
142.1
39.8
Job temp. is reached to 140±5°C i.e., from 136.2°C to 145.6°C at 9:30hrs on 10.5.2007 and it is maintained for 32hrs i.e. up to 17:30hrs on 11.5.2007.
Furnace is switched off at 17:30hrs on 11.5.2007 and circulation fans kept running till the job temperature is reached from 70°C- 75°C
Impregnated tubs for keeping jobs For vertical impregnation: As per respective tech. Document. For horizontal impregnation: As per respective tech. Document
Specifications of plant: Impregnation medium Epoxy resin (class F solvent free) and hardener mix in 1:1 ratio as per TG34967 Epoxy resin (class F solvent free) and hardener mix in 1:1 ratio as per TG34931 Horizontal impregnation chamber Diameter: 4000mm Cylindrical length: 9000 mm Operating over pressure: 6 bar Operating vacuum: 0.15 mbar Operating temperature: 90°C Loading weight of impregnation object: maximum of 120 tonnes Maximum leakage rate: less than 1mbar/lit/sec. Moving load: 140 tonnes. Static load: 170 tonnes
Pressure medium for impregnation Pressure medium: dry nitrogen Operating pressure: 6 bar. Nitrogen storage capacity: 52cubic meter at 25 bar. Resin storage capacity Total storage: 5*9000L+1*3000L Operating parameters of each tank Operating vacuum: 0.5mbar Operating over pressure: 0.5bar Operating temperature: 80°C Resin filters(stainless steel washable) Filter fineness: 150microns Output (maximum): 1000lits/min
Vacuum system Root pumps: 2No.s, 5.5KW each Suction capacity: 2000cubic meter/hr Vacuum pumps(4No.s, 7.5KW each) Suction capacity: 250 cubic meter/hr This system is provided with separator filter with activated carbon filters, to protect the vacuum pumps from resin and hardener vapours. Refrigeration system The resin inside the tanks has to be stored at 10±2°C. this can be stored for indefinite period with a brine chilling/refrigeration system. The brine storage capacity: 1*25000L+1*26000L Composition of brine: 40%Mono Ethylene glycol and 60%water Heating and cooling system The heating of resin in the storage tanks and the impregnation chamber is by circulating the heated brine through the heat exchangers, to heat by saturated steam. The hot brine is cooled to about 40°C by circulating water through coolers and then the brine is chilled to -10°C and stored in the tanks. Post heating of job Explosion proof steam drier and electrical heating superposed. Size: 7*4.5*4.5M Maximum weight of job: 80 tonnes Maximum temperature: 150°C Indirectly heated hot air circulating oven (gas fired) Size: 9*4.5*4.5M Maximum weight of job: 170 T/120T with facility for rotation. Maximum temperature: 150°C
DATA COLLECTION OF SAMPLES
INDO-BHARAT-II ROTOR
RESIN POOR SYSTEM
• • • • • •
RESIN RICH SYSTEM
The insulation tape used in this system has 40% resin. This method follows thermosetting process. There is a need for addition of resin from outside. Reduction in time cycle for this process
•
No tests are carried out while at processing Processing of bars along with stator and with conductors and processing of exciter Coils along with exciter is possible.
•
•
The cost of repair is more
•
The overall cost is less compared to resin rich system.
• • •
• • •
The insulation tape used in this is 7% of 40% resin. Same as in resin poor. Further addition of resin is not required from outside. It is very long process and time consuming while at processing stage. Tests are being carried out Stage. Processing of stator bars is only possible in resin rich systems. Repairing work is easy. The total cost in this process is more.
JUSTIFICATION
Justification can be done by two tests HV and TAN δ tests
PRESENT INSULATION SYSTEMS IN THE WORLD
1. Vacuum pressure impregnation (VPI) of individual coils and bars 2. Global VPI of complete stators 3. Hydraulic molding of individual coils and bars using resin-rich tapes 4. Press curing of individual coils and bars, also using resin-rich tapes
Westinghouse Electric Co.: Thermalastic™ General Electric Co. :Micapals I anII™,EpoxyMicaMat™, Micapal HT™, and hydromat™ Alsthom, GEC Alsthom, Alstom Power: Isotenax™, Resitherm™,
Siemens AG, KWU: Micalastic™
ABB Industrie AG: Micadur™, Toshiba Corporation: Tosrich™ and Tostight- I™ Mitsubishi Electric Corporation Hitachi, Ltd.: Hi-Resin™, Hi-Mold™, and Super Hi-Resin™ Summary of Present-Day Insulation Systems
A NEW hype IN INSULATION SYSTEM
MICALASTIC The MICALASTIC Insulation in ITAIPU™ Manufacturing and Design Fitting of Roebel Bars into Slots: Thermal Stability
CONCLUSION:
